DESCRIPTION: (Investigator's Abstract) The overall objective of this project is to gain a better understanding of the contributions of the orofacial motor mechanism (tongue, lips, jaw) to the swallowing process in both normal and surgical patient population. Swallowing is one of the most basic and important of all human biological functions. It is also one of the least understood. Historically, most of the physiological research on swallowing has focused on the pharyngeal and esophageal components using cineradiography and manometry. However, the importance of the oral component of swallowing is becoming increasingly apparent, both from the point of view of normal function and various neurologically and traumatically induced dysphagias. Since little data regarding the oral component of swallowing exist, and since theoretical considerations developed from other systems are not likely to apply to movements associated with swallowing, the identification and elucidation of the basic physiological mechanisms underlying the oral component of normal swallow represent a necessary prerequisite for understanding this important biological function and its clinical correlates. The specific aims of the study are to: (1) identify the primary muscles and muscle groups responsible for the oral phase of swallowing, and to determine if these muscles are organized into specific, reproducible patterns of activity; (2) using combined imaging and electromyographic techniques, to map the dynamic properties of tongue, lip, and jaw movements in positioning the bolus, fixing the base of the oral cavity, and effecting an anterior seal during swallowing; (3) determine if and how these patterns of movement and muscle actions vary with different individuals and bolus type; (4) determine the effects of oral cavity kinesthetic sensory input and mechanical conditions on the actions and coordination of lip, tongue, and jaw movement during swallowing; (5) determine the effects of oral and/or neck surgery on the orofacial mechanism during swallowing. This project will employ methods that will elucidate movements of the tongue body quantitatively in relation to the temporal and amplitude functions of the muscles that produce those movements. The ability to reveal the manner in which muscle activity correlates to particular oral movements during swallowing represents a new approach to study of swallowing function and one that will hopefully open a new area of research possibilities.